SpareDisk

How to free up disk space on a Mac

When your Mac says its disk is almost full, deleting files at random rarely helps much. Find out what is actually using the space first, then work from the largest items down. This guide goes through ten steps in the order that usually frees the most space for the least risk.

By Manish Bhattacharya, maker of SpareDisk · Updated

1. See what is using your storage

Open Apple menu › System Settings › General › Storage. The bar at the top splits used space into categories such as Applications, Documents, Photos, Developer and System Data. Click the ⓘ next to a category to see what is in it. The Recommendations section offers Store in iCloud, Optimize Storage and Empty Trash Automatically.

The categories are broad. They show that Documents takes 180 GB, but not which folders. A disk space analyzer such as SpareDisk draws the folders you choose as a treemap, so the largest ones stand out.

2. Empty the Trash, including app trash

Files you move to the Trash still take up space until you empty it. Some apps keep their own trash as well: Photos › Recently Deleted holds deleted photos for 30 days, and Mail keeps deleted messages in each account’s Trash. Empty these once you are sure you don’t need them.

3. Clear out Downloads

The Downloads folder collects installers (.dmg, .pkg), archives (.zip) and duplicate downloads such as report (1).pdf. In Finder, open Downloads, choose View › as List and click the Size column to sort by size. Installers can go once the app is installed.

4. Find large files

A few large files often matter more than thousands of small ones: virtual machine images, video exports, old Xcode installers, disk images and archives. See how to find large files on a Mac for four methods, from Finder search to Terminal.

5. Review old files and forgotten backups

Projects you finished years ago and old backup archives are easy candidates. Old iPhone and iPad backups also add up: in Finder, select your device in the sidebar and click Manage Backups to see and delete old ones. SpareDisk’s Older Files view charts bytes by the year files were last modified, so you can see how much space files older than three years take.

6. Remove duplicate files

The same file saved in two folders takes up space twice. Check that files are really identical, not just alike in name, before you delete a copy. How to find and remove duplicate files explains how to check safely.

7. Uninstall apps you don’t use, with their leftovers

Apps are often smaller than the data they keep in your Library: caches, containers, Application Support folders. Removing the app alone leaves that data behind. See how to uninstall apps on Mac completely.

8. Clear developer caches

If you write code, developer caches are often the biggest single win. Xcode DerivedData, simulators, device support files, Homebrew, npm and Docker can take tens of gigabytes. Most of it is rebuilt automatically when needed. See what is safe to delete.

9. Understand System Data before touching it

A large System Data figure is often caches, local Time Machine snapshots, virtual memory files and app data macOS does not put in a category. Some of it shrinks on its own. Read what System Data is on Mac before deleting anything in system folders.

10. Move what you want to keep

For files you want to keep but don’t need on the Mac, use an external drive, or turn on Store in iCloud so macOS keeps full-size copies in iCloud and downloads files only when you open them. Large photo libraries and video projects are the usual candidates.

What not to delete

  • Anything under /System, and system folders under /private.
  • The contents of your Photos or Music library package. Delete items inside the app instead.
  • Library folders for apps you still use, unless you know the app rebuilds them.
  • Files synced by iCloud Drive, Dropbox or OneDrive. Deleting them may delete them everywhere.

Move things to the Trash rather than deleting them permanently, and empty the Trash only once everything still works. SpareDisk works this way: it moves only items you confirm in Review, checks each item again before moving it, and leaves emptying the Trash to you.

Questions

How much free space should a Mac have?
A common rule of thumb is to keep 10 to 15 percent of the disk free, and at least 20 to 30 GB before a major macOS upgrade. macOS uses free space for virtual memory, caches and updates, and gets slow when the disk is nearly full.
Why didn’t my free space go up after deleting files?
Files in the Trash still use space until you empty it. Local Time Machine snapshots can also keep deleted data until macOS removes them. Cloned files, created when you duplicate a file in Finder on APFS, share storage, so deleting one copy may free very little.
What is purgeable space?
Purgeable space is space macOS can reclaim automatically when it is needed, such as cached iCloud files and old snapshots. It counts as available, so you don’t need to clear it yourself.
Is it safe to use a Mac cleaner app?
Choose one that shows you what it will remove and lets you review it first. Avoid one-click cleaners that remove system files automatically. SpareDisk never deletes anything automatically: you review every item, and it goes to the Trash.